drivers/staging/hv/storvsc_drv.c

   1 /*
   2  * Copyright (c) 2009, Microsoft Corporation.
   3  *
   4  * This program is free software; you can redistribute it and/or modify it
   5  * under the terms and conditions of the GNU General Public License,
   6  * version 2, as published by the Free Software Foundation.
   7  *
   8  * This program is distributed in the hope it will be useful, but WITHOUT
   9  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  10  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
  11  * more details.
  12  *
  13  * You should have received a copy of the GNU General Public License along with
  14  * this program; if not, write to the Free Software Foundation, Inc., 59 Temple
  15  * Place - Suite 330, Boston, MA 02111-1307 USA.
  16  *
  17  * Authors:
  18  *   Haiyang Zhang <haiyangz@microsoft.com>
  19  *   Hank Janssen  <hjanssen@microsoft.com>
  20  *   K. Y. Srinivasan <kys@microsoft.com>
  21  */
  22 #include <linux/init.h>
  23 #include <linux/slab.h>
  24 #include <linux/module.h>
  25 #include <linux/device.h>
  26 #include <linux/blkdev.h>
  27 #include <scsi/scsi.h>
  28 #include <scsi/scsi_cmnd.h>
  29 #include <scsi/scsi_host.h>
  30 #include <scsi/scsi_device.h>
  31 #include <scsi/scsi_tcq.h>
  32 #include <scsi/scsi_eh.h>
  33 #include <scsi/scsi_devinfo.h>
  34 #include <scsi/scsi_dbg.h>
  35
  36 #include "hyperv.h"
  37 #include "hyperv_storage.h"
  38
  39 static int storvsc_ringbuffer_size = STORVSC_RING_BUFFER_SIZE;
  40
  41 module_param(storvsc_ringbuffer_size, int, S_IRUGO);
  42 MODULE_PARM_DESC(storvsc_ringbuffer_size, "Ring buffer size (bytes)");
  43
  44 static const char *driver_name = "storvsc";
  45
  46 /* {ba6163d9-04a1-4d29-b605-72e2ffb1dc7f} */
  47 static const struct hv_guid gStorVscDeviceType = {
  48         .data = {
  49                 0xd9, 0x63, 0x61, 0xba, 0xa1, 0x04, 0x29, 0x4d,
  50                 0xb6, 0x05, 0x72, 0xe2, 0xff, 0xb1, 0xdc, 0x7f
  51         }
  52 };
  53
  54 struct hv_host_device {
  55         struct hv_device *dev;
  56         struct kmem_cache *request_pool;
  57         unsigned int port;
  58         unsigned char path;
  59         unsigned char target;
  60 };
  61
  62 struct storvsc_cmd_request {
  63         struct list_head entry;
  64         struct scsi_cmnd *cmd;
  65
  66         unsigned int bounce_sgl_count;
  67         struct scatterlist *bounce_sgl;
  68
  69         struct hv_storvsc_request request;
  70 };
  71
  72
  73 static int storvsc_device_alloc(struct scsi_device *sdevice)
  74 {
  75         /*
  76          * This enables luns to be located sparsely. Otherwise, we may not
  77          * discovered them.
  78          */
  79         sdevice->sdev_bflags |= BLIST_SPARSELUN | BLIST_LARGELUN;
  80         return 0;
  81 }
  82
  83 static int storvsc_merge_bvec(struct request_queue *q,
  84                               struct bvec_merge_data *bmd, struct bio_vec *bvec)
  85 {
  86         /* checking done by caller. */
  87         return bvec->bv_len;
  88 }
  89
  90 static int storvsc_device_configure(struct scsi_device *sdevice)
  91 {
  92         scsi_adjust_queue_depth(sdevice, MSG_SIMPLE_TAG,
  93                                 STORVSC_MAX_IO_REQUESTS);
  94
  95         DPRINT_INFO(STORVSC_DRV, "sdev (%p) - setting max segment size to %ld",
  96                     sdevice, PAGE_SIZE);
  97         blk_queue_max_segment_size(sdevice->request_queue, PAGE_SIZE);
  98
  99         DPRINT_INFO(STORVSC_DRV, "sdev (%p) - adding merge bio vec routine",
 100                     sdevice);
 101         blk_queue_merge_bvec(sdevice->request_queue, storvsc_merge_bvec);
 102
 103         blk_queue_bounce_limit(sdevice->request_queue, BLK_BOUNCE_ANY);
 104
 105         return 0;
 106 }
 107
 108 static void destroy_bounce_buffer(struct scatterlist *sgl,
 109                                   unsigned int sg_count)
 110 {
 111         int i;
 112         struct page *page_buf;
 113
 114         for (i = 0; i < sg_count; i++) {
 115                 page_buf = sg_page((&sgl[i]));
 116                 if (page_buf != NULL)
 117                         __free_page(page_buf);
 118         }
 119
 120         kfree(sgl);
 121 }
 122
 123 static int do_bounce_buffer(struct scatterlist *sgl, unsigned int sg_count)
 124 {
 125         int i;
 126
 127         /* No need to check */
 128         if (sg_count < 2)
 129                 return -1;
 130
 131         /* We have at least 2 sg entries */
 132         for (i = 0; i < sg_count; i++) {
 133                 if (i == 0) {
 134                         /* make sure 1st one does not have hole */
 135                         if (sgl[i].offset + sgl[i].length != PAGE_SIZE)
 136                                 return i;
 137                 } else if (i == sg_count - 1) {
 138                         /* make sure last one does not have hole */
 139                         if (sgl[i].offset != 0)
 140                                 return i;
 141                 } else {
 142                         /* make sure no hole in the middle */
 143                         if (sgl[i].length != PAGE_SIZE || sgl[i].offset != 0)
 144                                 return i;
 145                 }
 146         }
 147         return -1;
 148 }
 149
 150 static struct scatterlist *create_bounce_buffer(struct scatterlist *sgl,
 151                                                 unsigned int sg_count,
 152                                                 unsigned int len)
 153 {
 154         int i;
 155         int num_pages;
 156         struct scatterlist *bounce_sgl;
 157         struct page *page_buf;
 158
 159         num_pages = ALIGN(len, PAGE_SIZE) >> PAGE_SHIFT;
 160
 161         bounce_sgl = kcalloc(num_pages, sizeof(struct scatterlist), GFP_ATOMIC);
 162         if (!bounce_sgl)
 163                 return NULL;
 164
 165         for (i = 0; i < num_pages; i++) {
 166                 page_buf = alloc_page(GFP_ATOMIC);
 167                 if (!page_buf)
 168                         goto cleanup;
 169                 sg_set_page(&bounce_sgl[i], page_buf, 0, 0);
 170         }
 171
 172         return bounce_sgl;
 173
 174 cleanup:
 175         destroy_bounce_buffer(bounce_sgl, num_pages);
 176         return NULL;
 177 }
 178
 179
 180 /* Assume the original sgl has enough room */
 181 static unsigned int copy_from_bounce_buffer(struct scatterlist *orig_sgl,
 182                                             struct scatterlist *bounce_sgl,
 183                                             unsigned int orig_sgl_count)
 184 {
 185         int i;
 186         int j = 0;
 187         unsigned long src, dest;
 188         unsigned int srclen, destlen, copylen;
 189         unsigned int total_copied = 0;
 190         unsigned long bounce_addr = 0;
 191         unsigned long dest_addr = 0;
 192         unsigned long flags;
 193
 194         local_irq_save(flags);
 195
 196         for (i = 0; i < orig_sgl_count; i++) {
 197                 dest_addr = (unsigned long)kmap_atomic(sg_page((&orig_sgl[i])),
 198                                         KM_IRQ0) + orig_sgl[i].offset;
 199                 dest = dest_addr;
 200                 destlen = orig_sgl[i].length;
 201
 202                 if (bounce_addr == 0)
 203                         bounce_addr =
 204                         (unsigned long)kmap_atomic(sg_page((&bounce_sgl[j])),
 205                                                         KM_IRQ0);
 206
 207                 while (destlen) {
 208                         src = bounce_addr + bounce_sgl[j].offset;
 209                         srclen = bounce_sgl[j].length - bounce_sgl[j].offset;
 210
 211                         copylen = min(srclen, destlen);
 212                         memcpy((void *)dest, (void *)src, copylen);
 213
 214                         total_copied += copylen;
 215                         bounce_sgl[j].offset += copylen;
 216                         destlen -= copylen;
 217                         dest += copylen;
 218
 219                         if (bounce_sgl[j].offset == bounce_sgl[j].length) {
 220                                 /* full */
 221                                 kunmap_atomic((void *)bounce_addr, KM_IRQ0);
 222                                 j++;
 223
 224                                 /* if we need to use another bounce buffer */
 225                                 if (destlen || i != orig_sgl_count - 1)
 226                                         bounce_addr =
 227                                         (unsigned long)kmap_atomic(
 228                                         sg_page((&bounce_sgl[j])), KM_IRQ0);
 229                         } else if (destlen == 0 && i == orig_sgl_count - 1) {
 230                                 /* unmap the last bounce that is < PAGE_SIZE */
 231                                 kunmap_atomic((void *)bounce_addr, KM_IRQ0);
 232                         }
 233                 }
 234
 235                 kunmap_atomic((void *)(dest_addr - orig_sgl[i].offset),
 236                               KM_IRQ0);
 237         }
 238
 239         local_irq_restore(flags);
 240
 241         return total_copied;
 242 }
 243
 244
 245 /* Assume the bounce_sgl has enough room ie using the create_bounce_buffer() */
 246 static unsigned int copy_to_bounce_buffer(struct scatterlist *orig_sgl,
 247                                           struct scatterlist *bounce_sgl,
 248                                           unsigned int orig_sgl_count)
 249 {
 250         int i;
 251         int j = 0;
 252         unsigned long src, dest;
 253         unsigned int srclen, destlen, copylen;
 254         unsigned int total_copied = 0;
 255         unsigned long bounce_addr = 0;
 256         unsigned long src_addr = 0;
 257         unsigned long flags;
 258
 259         local_irq_save(flags);
 260
 261         for (i = 0; i < orig_sgl_count; i++) {
 262                 src_addr = (unsigned long)kmap_atomic(sg_page((&orig_sgl[i])),
 263                                 KM_IRQ0) + orig_sgl[i].offset;
 264                 src = src_addr;
 265                 srclen = orig_sgl[i].length;
 266
 267                 if (bounce_addr == 0)
 268                         bounce_addr =
 269                         (unsigned long)kmap_atomic(sg_page((&bounce_sgl[j])),
 270                                                 KM_IRQ0);
 271
 272                 while (srclen) {
 273                         /* assume bounce offset always == 0 */
 274                         dest = bounce_addr + bounce_sgl[j].length;
 275                         destlen = PAGE_SIZE - bounce_sgl[j].length;
 276
 277                         copylen = min(srclen, destlen);
 278                         memcpy((void *)dest, (void *)src, copylen);
 279
 280                         total_copied += copylen;
 281                         bounce_sgl[j].length += copylen;
 282                         srclen -= copylen;
 283                         src += copylen;
 284
 285                         if (bounce_sgl[j].length == PAGE_SIZE) {
 286                                 /* full..move to next entry */
 287                                 kunmap_atomic((void *)bounce_addr, KM_IRQ0);
 288                                 j++;
 289
 290                                 /* if we need to use another bounce buffer */
 291                                 if (srclen || i != orig_sgl_count - 1)
 292                                         bounce_addr =
 293                                         (unsigned long)kmap_atomic(
 294                                         sg_page((&bounce_sgl[j])), KM_IRQ0);
 295
 296                         } else if (srclen == 0 && i == orig_sgl_count - 1) {
 297                                 /* unmap the last bounce that is < PAGE_SIZE */
 298                                 kunmap_atomic((void *)bounce_addr, KM_IRQ0);
 299                         }
 300                 }
 301
 302                 kunmap_atomic((void *)(src_addr - orig_sgl[i].offset), KM_IRQ0);
 303         }
 304
 305         local_irq_restore(flags);
 306
 307         return total_copied;
 308 }
 309
 310
 311 /*
 312  * storvsc_remove - Callback when our device is removed
 313  */
 314 static int storvsc_remove(struct hv_device *dev)
 315 {
 316         struct Scsi_Host *host = dev_get_drvdata(&dev->device);
 317         struct hv_host_device *host_dev =
 318                         (struct hv_host_device *)host->hostdata;
 319
 320         /*
 321          * Call to the vsc driver to let it know that the device is being
 322          * removed
 323          */
 324         storvsc_dev_remove(dev);
 325
 326         if (host_dev->request_pool) {
 327                 kmem_cache_destroy(host_dev->request_pool);
 328                 host_dev->request_pool = NULL;
 329         }
 330
 331         DPRINT_INFO(STORVSC, "removing host adapter (%p)...", host);
 332         scsi_remove_host(host);
 333
 334         DPRINT_INFO(STORVSC, "releasing host adapter (%p)...", host);
 335         scsi_host_put(host);
 336         return 0;
 337 }
 338
 339
 340 static int storvsc_get_chs(struct scsi_device *sdev, struct block_device * bdev,
 341                            sector_t capacity, int *info)
 342 {
 343         sector_t nsect = capacity;
 344         sector_t cylinders = nsect;
 345         int heads, sectors_pt;
 346
 347         /*
 348          * We are making up these values; let us keep it simple.
 349          */
 350         heads = 0xff;
 351         sectors_pt = 0x3f;      /* Sectors per track */
 352         sector_div(cylinders, heads * sectors_pt);
 353         if ((sector_t)(cylinders + 1) * heads * sectors_pt < nsect)
 354                 cylinders = 0xffff;
 355
 356         info[0] = heads;
 357         info[1] = sectors_pt;
 358         info[2] = (int)cylinders;
 359
 360         DPRINT_INFO(STORVSC_DRV, "CHS (%d, %d, %d)", (int)cylinders, heads,
 361                         sectors_pt);
 362
 363         return 0;
 364 }
 365
 366 static int storvsc_host_reset(struct hv_device *device)
 367 {
 368         struct storvsc_device *stor_device;
 369         struct hv_storvsc_request *request;
 370         struct vstor_packet *vstor_packet;
 371         int ret, t;
 372
 373         DPRINT_INFO(STORVSC, "resetting host adapter...");
 374
 375         stor_device = get_stor_device(device);
 376         if (!stor_device)
 377                 return -1;
 378
 379         request = &stor_device->reset_request;
 380         vstor_packet = &request->vstor_packet;
 381
 382         init_completion(&request->wait_event);
 383
 384         vstor_packet->operation = VSTOR_OPERATION_RESET_BUS;
 385         vstor_packet->flags = REQUEST_COMPLETION_FLAG;
 386         vstor_packet->vm_srb.path_id = stor_device->path_id;
 387
 388         ret = vmbus_sendpacket(device->channel, vstor_packet,
 389                                sizeof(struct vstor_packet),
 390                                (unsigned long)&stor_device->reset_request,
 391                                VM_PKT_DATA_INBAND,
 392                                VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED);
 393         if (ret != 0)
 394                 goto cleanup;
 395
 396         t = wait_for_completion_timeout(&request->wait_event, HZ);
 397         if (t == 0) {
 398                 ret = -ETIMEDOUT;
 399                 goto cleanup;
 400         }
 401
 402         DPRINT_INFO(STORVSC, "host adapter reset completed");
 403
 404         /*
 405          * At this point, all outstanding requests in the adapter
 406          * should have been flushed out and return to us
 407          */
 408
 409 cleanup:
 410         put_stor_device(device);
 411         return ret;
 412 }
 413
 414
 415 /*
 416  * storvsc_host_reset_handler - Reset the scsi HBA
 417  */
 418 static int storvsc_host_reset_handler(struct scsi_cmnd *scmnd)
 419 {
 420         int ret;
 421         struct hv_host_device *host_dev =
 422                 (struct hv_host_device *)scmnd->device->host->hostdata;
 423         struct hv_device *dev = host_dev->dev;
 424
 425         DPRINT_INFO(STORVSC_DRV, "sdev (%p) dev obj (%p) - host resetting...",
 426                     scmnd->device, dev);
 427
 428         /* Invokes the vsc to reset the host/bus */
 429         ret = storvsc_host_reset(dev);
 430         if (ret != 0)
 431                 return ret;
 432
 433         DPRINT_INFO(STORVSC_DRV, "sdev (%p) dev obj (%p) - host reseted",
 434                     scmnd->device, dev);
 435
 436         return ret;
 437 }
 438
 439
 440 /*
 441  * storvsc_commmand_completion - Command completion processing
 442  */
 443 static void storvsc_commmand_completion(struct hv_storvsc_request *request)
 444 {
 445         struct storvsc_cmd_request *cmd_request =
 446                 (struct storvsc_cmd_request *)request->context;
 447         struct scsi_cmnd *scmnd = cmd_request->cmd;
 448         struct hv_host_device *host_dev =
 449                 (struct hv_host_device *)scmnd->device->host->hostdata;
 450         void (*scsi_done_fn)(struct scsi_cmnd *);
 451         struct scsi_sense_hdr sense_hdr;
 452         struct vmscsi_request *vm_srb;
 453
 454         if (cmd_request->bounce_sgl_count) {
 455
 456                 /* FIXME: We can optimize on writes by just skipping this */
 457                 copy_from_bounce_buffer(scsi_sglist(scmnd),
 458                                         cmd_request->bounce_sgl,
 459                                         scsi_sg_count(scmnd));
 460                 destroy_bounce_buffer(cmd_request->bounce_sgl,
 461                                       cmd_request->bounce_sgl_count);
 462         }
 463
 464         vm_srb = &request->vstor_packet.vm_srb;
 465         scmnd->result = vm_srb->scsi_status;
 466
 467         if (scmnd->result) {
 468                 if (scsi_normalize_sense(scmnd->sense_buffer,
 469                                 SCSI_SENSE_BUFFERSIZE, &sense_hdr))
 470                         scsi_print_sense_hdr("storvsc", &sense_hdr);
 471         }
 472
 473         scsi_set_resid(scmnd,
 474                 request->data_buffer.len -
 475                 vm_srb->data_transfer_length);
 476
 477         scsi_done_fn = scmnd->scsi_done;
 478
 479         scmnd->host_scribble = NULL;
 480         scmnd->scsi_done = NULL;
 481
 482         /* !!DO NOT MODIFY the scmnd after this call */
 483         scsi_done_fn(scmnd);
 484
 485         kmem_cache_free(host_dev->request_pool, cmd_request);
 486 }
 487
 488
 489 /*
 490  * storvsc_queuecommand - Initiate command processing
 491  */
 492 static int storvsc_queuecommand_lck(struct scsi_cmnd *scmnd,
 493                                 void (*done)(struct scsi_cmnd *))
 494 {
 495         int ret;
 496         struct hv_host_device *host_dev =
 497                 (struct hv_host_device *)scmnd->device->host->hostdata;
 498         struct hv_device *dev = host_dev->dev;
 499         struct hv_storvsc_request *request;
 500         struct storvsc_cmd_request *cmd_request;
 501         unsigned int request_size = 0;
 502         int i;
 503         struct scatterlist *sgl;
 504         unsigned int sg_count = 0;
 505         struct vmscsi_request *vm_srb;
 506
 507
 508         /* If retrying, no need to prep the cmd */
 509         if (scmnd->host_scribble) {
 510
 511                 cmd_request =
 512                         (struct storvsc_cmd_request *)scmnd->host_scribble;
 513                 DPRINT_INFO(STORVSC_DRV, "retrying scmnd %p cmd_request %p",
 514                             scmnd, cmd_request);
 515
 516                 goto retry_request;
 517         }
 518
 519         scmnd->scsi_done = done;
 520
 521         request_size = sizeof(struct storvsc_cmd_request);
 522
 523         cmd_request = kmem_cache_zalloc(host_dev->request_pool,
 524                                        GFP_ATOMIC);
 525         if (!cmd_request) {
 526                 scmnd->scsi_done = NULL;
 527                 return SCSI_MLQUEUE_DEVICE_BUSY;
 528         }
 529
 530         /* Setup the cmd request */
 531         cmd_request->bounce_sgl_count = 0;
 532         cmd_request->bounce_sgl = NULL;
 533         cmd_request->cmd = scmnd;
 534
 535         scmnd->host_scribble = (unsigned char *)cmd_request;
 536
 537         request = &cmd_request->request;
 538         vm_srb = &request->vstor_packet.vm_srb;
 539
 540
 541         /* Build the SRB */
 542         switch (scmnd->sc_data_direction) {
 543         case DMA_TO_DEVICE:
 544                 vm_srb->data_in = WRITE_TYPE;
 545                 break;
 546         case DMA_FROM_DEVICE:
 547                 vm_srb->data_in = READ_TYPE;
 548                 break;
 549         default:
 550                 vm_srb->data_in = UNKNOWN_TYPE;
 551                 break;
 552         }
 553
 554         request->on_io_completion = storvsc_commmand_completion;
 555         request->context = cmd_request;/* scmnd; */
 556
 557         vm_srb->port_number = host_dev->port;
 558         vm_srb->path_id = scmnd->device->channel;
 559         vm_srb->target_id = scmnd->device->id;
 560         vm_srb->lun = scmnd->device->lun;
 561
 562         vm_srb->cdb_length = scmnd->cmd_len;
 563
 564         memcpy(vm_srb->cdb, scmnd->cmnd, vm_srb->cdb_length);
 565
 566         request->sense_buffer = scmnd->sense_buffer;
 567
 568
 569         request->data_buffer.len = scsi_bufflen(scmnd);
 570         if (scsi_sg_count(scmnd)) {
 571                 sgl = (struct scatterlist *)scsi_sglist(scmnd);
 572                 sg_count = scsi_sg_count(scmnd);
 573
 574                 /* check if we need to bounce the sgl */
 575                 if (do_bounce_buffer(sgl, scsi_sg_count(scmnd)) != -1) {
 576                         cmd_request->bounce_sgl =
 577                                 create_bounce_buffer(sgl, scsi_sg_count(scmnd),
 578                                                      scsi_bufflen(scmnd));
 579                         if (!cmd_request->bounce_sgl) {
 580                                 scmnd->scsi_done = NULL;
 581                                 scmnd->host_scribble = NULL;
 582                                 kmem_cache_free(host_dev->request_pool,
 583                                                 cmd_request);
 584
 585                                 return SCSI_MLQUEUE_HOST_BUSY;
 586                         }
 587
 588                         cmd_request->bounce_sgl_count =
 589                                 ALIGN(scsi_bufflen(scmnd), PAGE_SIZE) >>
 590                                         PAGE_SHIFT;
 591
 592                         /*
 593                          * FIXME: We can optimize on reads by just skipping
 594                          * this
 595                          */
 596                         copy_to_bounce_buffer(sgl, cmd_request->bounce_sgl,
 597                                               scsi_sg_count(scmnd));
 598
 599                         sgl = cmd_request->bounce_sgl;
 600                         sg_count = cmd_request->bounce_sgl_count;
 601                 }
 602
 603                 request->data_buffer.offset = sgl[0].offset;
 604
 605                 for (i = 0; i < sg_count; i++)
 606                         request->data_buffer.pfn_array[i] =
 607                                 page_to_pfn(sg_page((&sgl[i])));
 608
 609         } else if (scsi_sglist(scmnd)) {
 610                 request->data_buffer.offset =
 611                         virt_to_phys(scsi_sglist(scmnd)) & (PAGE_SIZE-1);
 612                 request->data_buffer.pfn_array[0] =
 613                         virt_to_phys(scsi_sglist(scmnd)) >> PAGE_SHIFT;
 614         }
 615
 616 retry_request:
 617         /* Invokes the vsc to start an IO */
 618         ret = storvsc_do_io(dev, &cmd_request->request);
 619
 620         if (ret == -1) {
 621                 /* no more space */
 622
 623                 if (cmd_request->bounce_sgl_count) {
 624                         /*
 625                          * FIXME: We can optimize on writes by just skipping
 626                          * this
 627                          */
 628                         copy_from_bounce_buffer(scsi_sglist(scmnd),
 629                                                 cmd_request->bounce_sgl,
 630                                                 scsi_sg_count(scmnd));
 631                         destroy_bounce_buffer(cmd_request->bounce_sgl,
 632                                               cmd_request->bounce_sgl_count);
 633                 }
 634
 635                 kmem_cache_free(host_dev->request_pool, cmd_request);
 636
 637                 scmnd->scsi_done = NULL;
 638                 scmnd->host_scribble = NULL;
 639
 640                 ret = SCSI_MLQUEUE_DEVICE_BUSY;
 641         }
 642
 643         return ret;
 644 }
 645
 646 static DEF_SCSI_QCMD(storvsc_queuecommand)
 647
 648
 649 /* Scsi driver */
 650 static struct scsi_host_template scsi_driver = {
 651         .module =               THIS_MODULE,
 652         .name =                 "storvsc_host_t",
 653         .bios_param =           storvsc_get_chs,
 654         .queuecommand =         storvsc_queuecommand,
 655         .eh_host_reset_handler =        storvsc_host_reset_handler,
 656         .slave_alloc =          storvsc_device_alloc,
 657         .slave_configure =      storvsc_device_configure,
 658         .cmd_per_lun =          1,
 659         /* 64 max_queue * 1 target */
 660         .can_queue =            STORVSC_MAX_IO_REQUESTS*STORVSC_MAX_TARGETS,
 661         .this_id =              -1,
 662         /* no use setting to 0 since ll_blk_rw reset it to 1 */
 663         /* currently 32 */
 664         .sg_tablesize =         MAX_MULTIPAGE_BUFFER_COUNT,
 665         /*
 666          * ENABLE_CLUSTERING allows mutiple physically contig bio_vecs to merge
 667          * into 1 sg element. If set, we must limit the max_segment_size to
 668          * PAGE_SIZE, otherwise we may get 1 sg element that represents
 669          * multiple
 670          */
 671         /* physically contig pfns (ie sg[x].length > PAGE_SIZE). */
 672         .use_clustering =       ENABLE_CLUSTERING,
 673         /* Make sure we dont get a sg segment crosses a page boundary */
 674         .dma_boundary =         PAGE_SIZE-1,
 675 };
 676
 677
 678 /*
 679  * storvsc_probe - Add a new device for this driver
 680  */
 681
 682 static int storvsc_probe(struct hv_device *device)
 683 {
 684         int ret;
 685         struct Scsi_Host *host;
 686         struct hv_host_device *host_dev;
 687         struct storvsc_device_info device_info;
 688
 689         host = scsi_host_alloc(&scsi_driver,
 690                                sizeof(struct hv_host_device));
 691         if (!host)
 692                 return -ENOMEM;
 693
 694         dev_set_drvdata(&device->device, host);
 695
 696         host_dev = (struct hv_host_device *)host->hostdata;
 697         memset(host_dev, 0, sizeof(struct hv_host_device));
 698
 699         host_dev->port = host->host_no;
 700         host_dev->dev = device;
 701
 702         host_dev->request_pool =
 703                                 kmem_cache_create(dev_name(&device->device),
 704                                         sizeof(struct storvsc_cmd_request), 0,
 705                                         SLAB_HWCACHE_ALIGN, NULL);
 706
 707         if (!host_dev->request_pool) {
 708                 scsi_host_put(host);
 709                 return -ENOMEM;
 710         }
 711
 712         device_info.port_number = host->host_no;
 713         device_info.ring_buffer_size  = storvsc_ringbuffer_size;
 714         /* Call to the vsc driver to add the device */
 715         ret = storvsc_dev_add(device, (void *)&device_info);
 716
 717         if (ret != 0) {
 718                 kmem_cache_destroy(host_dev->request_pool);
 719                 scsi_host_put(host);
 720                 return -1;
 721         }
 722
 723         host_dev->path = device_info.path_id;
 724         host_dev->target = device_info.target_id;
 725
 726         /* max # of devices per target */
 727         host->max_lun = STORVSC_MAX_LUNS_PER_TARGET;
 728         /* max # of targets per channel */
 729         host->max_id = STORVSC_MAX_TARGETS;
 730         /* max # of channels */
 731         host->max_channel = STORVSC_MAX_CHANNELS - 1;
 732
 733         /* Register the HBA and start the scsi bus scan */
 734         ret = scsi_add_host(host, &device->device);
 735         if (ret != 0) {
 736
 737                 storvsc_dev_remove(device);
 738
 739                 kmem_cache_destroy(host_dev->request_pool);
 740                 scsi_host_put(host);
 741                 return -1;
 742         }
 743
 744         scsi_scan_host(host);
 745         return ret;
 746 }
 747
 748 /* The one and only one */
 749
 750 static struct hv_driver storvsc_drv = {
 751         .probe = storvsc_probe,
 752         .remove = storvsc_remove,
 753 };
 754
 755
 756 /*
 757  * storvsc_drv_init - StorVsc driver initialization.
 758  */
 759 static int storvsc_drv_init(void)
 760 {
 761         int ret;
 762         struct hv_driver *drv = &storvsc_drv;
 763         u32 max_outstanding_req_per_channel;
 764
 765         /*
 766          * Divide the ring buffer data size (which is 1 page less
 767          * than the ring buffer size since that page is reserved for
 768          * the ring buffer indices) by the max request size (which is
 769          * vmbus_channel_packet_multipage_buffer + struct vstor_packet + u64)
 770          */
 771
 772         max_outstanding_req_per_channel =
 773         ((storvsc_ringbuffer_size - PAGE_SIZE) /
 774         ALIGN(MAX_MULTIPAGE_BUFFER_PACKET +
 775         sizeof(struct vstor_packet) + sizeof(u64),
 776         sizeof(u64)));
 777
 778         memcpy(&drv->dev_type, &gStorVscDeviceType,
 779                sizeof(struct hv_guid));
 780
 781         if (max_outstanding_req_per_channel <
 782             STORVSC_MAX_IO_REQUESTS)
 783                 return -1;
 784
 785         drv->name = driver_name;
 786         drv->driver.name = driver_name;
 787
 788
 789         /* The driver belongs to vmbus */
 790         ret = vmbus_child_driver_register(&drv->driver);
 791
 792         return ret;
 793 }
 794
 795 static void storvsc_drv_exit(void)
 796 {
 797         vmbus_child_driver_unregister(&storvsc_drv.driver);
 798 }
 799
 800 static int __init storvsc_init(void)
 801 {
 802         int ret;
 803
 804         DPRINT_INFO(STORVSC_DRV, "Storvsc initializing....");
 805         ret = storvsc_drv_init();
 806         return ret;
 807 }
 808
 809 static void __exit storvsc_exit(void)
 810 {
 811         storvsc_drv_exit();
 812 }
 813
 814 MODULE_LICENSE("GPL");
 815 MODULE_VERSION(HV_DRV_VERSION);
 816 MODULE_DESCRIPTION("Microsoft Hyper-V virtual storage driver");
 817 module_init(storvsc_init);
 818 module_exit(storvsc_exit);